Trickle charger

[HVSTRINE]

I am wondering if I hook up an auto trickle charger to my dual battery system if it would keep both batteries charged. The batteries are installed in the boat with an 1-2-both/off switch. Could this cause problems? It seems like it would top off both batteries but maybe it would just kick off after topping off the one I connected it to. I wonder if I could hook it to the common and take care of both?

 

[Bob_VT]

Re: Trickle charger

You really need two chargers or a charger that will handle multiple batteries.

 

[Barnacle_Bill]

Re: Trickle charger

DON"T DO IT!!. Using a trickle charger in that manner would be putting your batteries in parallel. Since you basically isolate them with the switch you would have max smoke and possibly a fire the frist time you started the motor. A 2 bank smart charger or 2 trickle chargers like Bob said would work.

 

[dan t.]

Re: Trickle charger

hook to 1 battery set switch to both. I do it all the time,no smoke,or hook pos to com on switch neg to ground on motor, will charge 1, 2,or both where ever you set the switch

 

[Chris1956]

Re: Trickle charger

If your batteries are set up as two 12V batteries(versus a 24V system), you have two choices to charge them with that charger. The first is to set the battery switch to both, and connect the charger to either battery. They will both charge.

If you are apprehensive about leaving "power on" to the boat, set the battery switch to off, and connect the trickle charger to one battery. Now place a small jumper wire from the positive pole of one battery to the positive pole of the other battery. This will allow your trickle charger to charge both batteries.

BTW - If the charger is a 1-2Amp charger, you can let it charge continuously. That small current flow across one or two batteries will keep it "topped" off, due to the automatic taper of the charge as the voltage rises, but will never overcharge.

 

[sschefer]

Re: Trickle charger

I am wondering if I hook up an auto trickle charger to my dual battery system if it would keep both batteries charged. The batteries are installed in the boat with an 1-2-both/off switch. Could this cause problems? It seems like it would top off both batteries but maybe it would just kick off after topping off the one I connected it to. I wonder if I could hook it to the common and take care of both?

Assumption: 12vdc system (not 24 or 36)
Questions that need answering:

1. Are these batteries automotive batteries, marine starting batteries or marine deep cylcle batteries?
2. Are they standard lead acid batteries, Absorbent Glass Mat (AGM), Gell Cell, other.
3. Are both batteries identical?

Here's why - automotive and marine starting batteries will normally charge fine with an automotive charger. A deep cycle marine battery needs a charger that is designed for them. Most newer marine chargers can sense the type of battery they are connected to and charge accordingly. Many of them can't do a AGM correctly and most won't do Gel Cells.

Charging in the "Both" position. Well, no.. not unless both batteries are identical. The "Both" postion is supposed to be used only when you've accidently drained your starting battery and you need a boost to get the boat running.
My guess is that the automotive charger would not be able to adjust for the type of battery it is trying charge and revert back to something safe or shut off. Something safe would be probably be inadequate for charging a deepcycle and cause the deepcycle to attempt to charge itself from the starting battery with an end result of two poorly charged batteries.

 

[HVSTRINE]

Re: Trickle charger

Assumption: 12vdc system (not 24 or 36)
Questions that need answering:

1. Are these batteries automotive batteries, marine starting batteries or marine deep cylcle batteries?
2. Are they standard lead acid batteries, Absorbent Glass Mat (AGM), Gell Cell, other.
3. Are both batteries identical?QUOTE]
System is 12v.
Both are Marine starting batteries, standard lead acid, not identical except for age~. CCA is different. Charger is 1.5 amp auto shut-off at full charge.

 

[triumphrick]

Re: Trickle charger

Well, if one were to read every reply to this post, he would be thoroughly confused, as the OP may be right now. Yes, your automotive type charger can charge the two batteries as was mentioned. However, it's much less of a hassle to mount an on board dual bank marine charger that all you will need to do is plug in and leave plugged in while ashore, in the garage, driveway, etc. Pro mariner, guest, dual pro and minn kota all make applicable chargers. Good luck!

 

[HVSTRINE]

Re: Trickle charger

Your right, the answers have varied from simple to catastrophic. I kinda like the ones that say go for it, since the state of my current boating finances is in need of a bail-out. And since I already own a brand new 1.5A trickle charger....

 

[clarkbre]

Re: Trickle charger

I totally agree with triumphrick. Do it the right way the first time. I bought the Minnkota onboard battery charger/maintainer and it works great. It makes the battery completely maintenance free because you just leave it plugged in all the time. They're not too expensive and they're nice because no matter where your boat is, it's always there. I have the single battery charger but you can buy them for multiple batteries. Here's the link:

http://www.cabelas.com/cabelas/en/templates/links/link.jsp?id=0000972014360a&type=product&cmCat=SEARCH_all&returnPage=search-results1.jsp&Ntt=minnkota+charger&Ntk=Products&sort=all&_D%3AhasJS=+&N=0&_D%3Asort=+&Nty=1&hasJS=true&_DARGS=%2Fcabelas%2Fen%2Fcommon%2Fsearch%2Fsearch-box.jsp.form1&_dyncharset=ISO-8859-1

 

[Chris1956]

Re: Trickle charger

HVStrine, Your 1.5A trickle charger is perfect for charging those batteries. I would set the battery switch to off, connect the charger to one battery, put a jumper from that batts positive pole to the other batteries positive pole, plug in the charger, and leave it alone until spring. 1.5 Amps will barely keep those batteries "warm", and they will be fully charged come boating season.

The only time you need a built in charging system is when you have a cruiser or some other boat with lots of electrical stuff (Fridge, stove, micro...), that you want to use at the dock, and out on the water, and you have no generator. On that kind of boat, you tend to run down the "House" deep cycle batteries, and use the built in charger to charge them up, upon return to the dock.

 

[HVSTRINE]

Re: Trickle charger

Thanks Chris1956, I'll try what you said, however after reading the manual, I discovered that the charger shuts off after reaching 12v charge. Will this stop it from topping off the 2nd btry or will tying the positives together raise the charge simultaneously on both?

 

[pvanv]

Re: Trickle charger

Actually, a 12v NOMINAL battery is nearly dead at 12v. Figure charging will top up to about 13.6 while under charge. The consumer-grade literature usually over-simplifies things like that.

Assuming the batteries connected in parallel (either setting the switch to BOTH or adding a charging jumper between (+) posts), you will get parallel charging -- which is fine. Assuming regular flooded starting batteries, a 1.5a trickle charger will keep them both topped up just fine. Whoever suggested smoke coming from that arrangement doesn't understand basic electrical principles.

It will work just fine in the garage or driveway.

One caution: Understand that a terrestrial-designed (non-marine) charger will not be an option on the water. In addition to being intolerant of splashes, most automotive-type chargers have tremendous AC leakage, which won't necessarily hurt the batteries, but will accelerate corrosion of any grounded metal in the water. I have seem lower units completely corroded through because of that sort of installation. So it will be limited to on-shore charging.

 

[sschefer]

Re: Trickle charger

Agree with the posts regarding the trickle chargers and the starting batteries. Your charger will work fine. An onboard charging system would be the cat's meow but not necessary in your case. You can also charge in the "Both" position but it will take twice as long to obtain a full charge.

I have heard that when running in the both mode, you should let the batteries equalize first and that does make some sense since the first battery that comes to full might cause the charger to shut down. I don't think that would be the case if the charger is in trickle or maintenance mode. You would have to try it and see.

 

[mphy98]

Re: Trickle charger

uh, why not pick up a couple of cheap battery tenders, they are sold for the collector car market, i have a couple of them on a few of my cars, and on the boat batteries as well. sealed units no chance for spark from gas from the batteries or fuel. perfect solution and not expensive at all.

 

[sschefer]

Re: Trickle charger

uh, why not pick up a couple of cheap battery tenders, they are sold for the collector car market, i have a couple of them on a few of my cars, and on the boat batteries as well. sealed units no chance for spark from gas from the batteries or fuel. perfect solution and not expensive at all.

Great suggestion, I have one. I think he's got what he's got and wants to use it rather than spend more money.

 

[mphy98]

Re: Trickle charger

I understand, but most trickle and other battery chargers are vented, that could cause a fire with the possibility of fumes and vapors. I would go with a tender just for safety.

 

[Silvertip]

Re: Trickle charger

I agree that there is some mis-information here -- especially regarding "smoke and fire". Put the charger on either battery, set the battery switch to BOTH and be done with it. Or connect to the COM terminal as was also suggested. There is no reason to allow the batteries to equalize since the charger is looking at the SYSTEM which in this case is paralleled batteries -- not individual batteries. Besides, within a couple of minutes, if one battery is significantly more discharged than the other they will equalize quickly whether or not the charger is connected. Even if they don't equalize quickly, the charger will simply cycle its profile (charge/float) until they are equal.

 

[Barnacle_Bill]

Re: Trickle charger

I got the impression in his original post that he wanted to connect the charger directly to both batteries. Going thru the switch does change things.

 

[slasmith1]

Re: Trickle charger

by reading this thread I am guessing that you are planning on setting this up in your engine compartment. if that is the case it is a very bad idea the only way I would use a automotive charger is to remove the batteries from the boat to charge them. This is for the same reason you should never use automotive electrical parts on your engine. It is in an enclosed engine/bilge area subject to vapor build up and these are not ignition protected devices.

My advice is to purchase the proper marine charger and correctly install it. This will avoid a possibly embarrassing conversation with your insurance agent later.(after the explosion)